Sewing machine controller

ABSTRACT

A controller for a sewing machine includes a driving motor 7 for driving a main shaft of a sewing machine head; a detecting unit 9 having a rotation-angle detecting means for detecting a rotational angle of the motor 7; a control section 40 for controlling the motor 7 and receiving a detection signal of the detecting unit 9; an operating section 30 for instructing the operation of the sewing machine; a designating means 34 provided in the control section 40 or the operating section 30 for designating a predetermined position in a vertically moving process of a needle 5 of the sewing machine; and a first memory portion 55 and a second memory portion 131 capable of storing and reading a value designated by the designating means, wherein the first memory portion 55 is provided in the control section 40, and the second memory portion 131 is provided in the detecting unit 9 or the operating section 30.

TECHNICAL FIELD

The present invention relates to a controller for a sewing machine usingan encoder for detecting the angle of rotation of a motor for driving aneedle, so as to overcome drawbacks which occur at the time ofreplacement of the motor.

BACKGROUND ART

Referring to FIGS. 5 to 7, a description will be given of a conventionalsewing machine. In FIGS. 5 and 6, a sewing machine is comprised of adriving section 1 having a motor 7 for effecting such as the verticalmovement of a needle 5, an operating section 30 for imparting a controlcommand to the driving section 1, and a control section 40 for drivingand controlling the driving section 1 on the basis of the command fromthe operating section 30.

The driving section 1 is connected to a solenoid 3 for driving a sewingmachine head, through a motor-side pulley 19 connected to a shaft of amotor 7 meshing with a timing belt 17, and through a sewing-machine-sidepulley 15 connected to a shaft 11 of the sewing machine meshing with thetiming belt 17. It should be noted that an encoder 9 serving as arotational-angle detecting means for detecting the rotational angle ofthe motor 7 is connected to the shaft of the motor 7, and a needleposition detector 13 for detecting an upper position, shown in FIG. 7,of the needle 5 is connected to an end of the shaft 11 of the sewingmachine.

The operating section 30 has a plurality of switches 32 for impartingcommands to the driving section 1, the solenoid 3, the encoder 9, andthe like, as well as a display unit 36 constituted by a liquid-crystaldisplay for displaying the contents of operation of the switches 32.

The control section 40 has a control-command generating unit 50 forgenerating commands for controlling the motor 7, the encoder 9, and thelike, as well as a driving unit 60 for obtaining a signal for drivingthe encoder 7 on the basis of a signal from the control-commandgenerating unit 50.

The control-command generating unit 50 has an interface portion(hereafter referred to as the I/O) serving as a connecting portion fortransmitting and receiving electrical signals with respect to theoperating section 30; an I/O 52 serving as a connecting portion fortransmitting and receiving electrical signals to and from the encoder 9;a CPU 53 for supervising and controlling; a nonvolatile memory portion(hereafter referred to as the control memory) 55 for storing variousdata and capable of electrically writing and erasing the data; and anI/O 57 serving as a connecting portion for transmitting an electricalsignal to the driving section 60.

The driving unit 60 has an I/O 62 for receiving an electrical signalfrom the I/O 57 of the control-command generating unit 50, as well as anI/O 64 for transmitting an electrical signal to the motor 7. Connectors70 and 72 are provided for detachably connecting output lines of thecontrol section to a lead wire of the motor 7 and a lead wire of theencoder 9.

Since the conventional sewing machine is configured as described above,there have been drawbacks in that since an unillustrated upper-positiondetecting disk inside the needle position detector 13 is attached to theshaft 11 of the sewing machine and rotates at high speed, theupper-position detecting disk is liable to break down, and since thesewing machine must be driven after positioning the disk, the operationis intricate.

To overcome such drawbacks, it is conceivable to provide an arrangementin which, as shown in FIG. 6, an angle setting switch 34 is added forsetting the angle of the motor 7 corresponding to the upper position ofthe needle 5 (this angle will be hereafter referred to as theupper-position angle), and to effect the operation as will be describedbelow.

First, after the power supply of the control section 40 is turned on,the operator moves the needle 5 to the point of upper position thereof,i.e., to the value A (a motor rotation angle Ua) of a sawtooth outputwaveform of the encoder 9, as shown in FIG. 7. If the operator thenturns on the angle setting switch 34, the display unit displays "UPSET,"and the state is set in the set standby state. If the operator turns onthe angle setting switch 34 again, the control CPU 53 stores the valueUa of the upper-position angle (the output waveform value A of theencoder 9) in the control memory 55. At this upper-position angle, thesewing machine is readily operable.

However, if the motor 7 breaks down due to some cause or other and isreplaced with another motor 7, since a reference point of the rotatingposition is provided on the sewing machine-side pulley 19 to simplifythe adjustment, and the sewing machine-side pulley 19 is connected tothe motor shaft 11 through the timing belt 17, the reference point forthe motor-side pulley 15 deviates, and the sawtooth output waveform ofthe encoder 7 becomes those shown at the solid lines and the chain linesas shown in FIG. 7, so that the upper-position angle changes from Ua toUi, thereby producing a large error in the detection of the upperposition of the needle 5. Accordingly, there has been a problem in thatif the sewing machine is driven on the basis of this error, the sewnobject is conceivably difficult to remove from the needle 5.

In addition, there has been another problem in that in a case where thecontrol section 40 has broken down, if the control section is replaced,since only the control section 40 stores the upper-position angle of theneedle 5, the upper-position angle must be set again, which istroublesome.

DISCLOSURE OF THE INVENTION

The present invention is provided to overcome the above-describedproblems, and the object thereof is to provide a simple controller for asewing machine in which drawbacks are difficult to occur even if thecontrol section or the motor is replaced.

To attain this object, according to a first aspect of the presentinvention, a controller for a sewing machine comprises: a driving motorfor driving a main shaft of a sewing machine head; a detecting unithaving a rotation-angle detecting means for detecting a rotational angleof the motor; a control unit for controlling the motor and receiving adetection signal of the detecting unit; an operating section forinstructing the operation of the sewing machine; a designating meansprovided in the control section or the operating section for designatinga predetermined position in a vertically moving process of a needle ofthe sewing machine; and a first memory portion and a second memoryportion capable of storing and reading a value designated by thedesignating means, wherein the first memory portion is provided in thecontrol section, and the second memory portion is provided in thedetecting unit or the operating section.

According to a second aspect of the present invention, a controller fora sewing machine comprises: a driving motor for driving a main shaft ofa sewing machine head; a motor-replacement detecting means for detectingthat the motor has been replaced with another motor; and a startingprohibiting means for prohibiting the starting of the motor if thereplacement is detected by the motor-replacement detecting means.

According to a third aspect of the present invention, a controller for asewing machine comprises: a driving motor for driving a main shaft of asewing machine head; a motor-replacement detecting means for detectingthat the motor has been replaced with another motor; and a designatingmeans for designating a predetermined position of the needle if thereplacement is detected by the motor-replacement detecting means.

According to a fourth aspect of the present invention, a controller fora sewing machine is characterized in that the motor-replacementdetecting means comprises: a value designating means for designating anidentification value of the motor; an identification-value storing meansfor storing the identification value designated by the value designatingmeans; and a determining means for determining whether or not theidentification value of the motor and the identification value ofanother motor agree with each other.

According to a fifth aspect of the present invention, a controller for asewing machine is characterized in that the motor-replacement detectingmeans comprises: a voltage detecting unit for effecting the detection bythe attenuation of a voltage value of the detecting unit, an assumptionbeing made on the basis of the attenuation of the voltage value of thevoltage detecting unit that the motor has been replaced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an overall controller for asewing machine in accordance with an embodiment of the presentinvention;

FIG. 2 is a flowchart illustrating the operation of the controller for asewing machine shown in FIG. 1;

FIG. 3 is a flowchart illustrating other operation of the controller fora sewing machine shown in FIG. 1;

FIG. 4 is a flowchart illustrating still other operation of thecontroller for a sewing machine shown in FIG. 1;

FIG. 5 is an overall schematic diagram of the sewing machine;

FIG. 6 is a block diagram of a conventional controller for a sewingmachine; and

FIG. 7 is a movement curve illustrating the vertical motion of a needleand a curve illustrating an output value of an encoder.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, a description will be given hereafter of the embodiments of thepresent invention.

First Embodiment

Referring to FIG. 1, a description will be given of an embodiment of thepresent invention. FIG. 1 is a block diagram illustrating an overallcontroller for a sewing machine. In the drawing, the same referencenumerals as those of the conventional controller indicate identical orcorresponding portions, and a description thereof will be omitted.

The controller for a sewing machine comprises an operating section 30, acontrol section 40, and an encoder controlling section 180. Theoperating section 30 has a command memory 131 constituted by anonvolatile storage device capable of electrically reading and writing,a read switch 136, and a write switch 138.

The control section 40 has a battery 101 for backup, and the encodercontrolling section 180 has a voltage detecting unit 181 for detectingwhether or not a supply voltage has been supplied from the controlsection 40, an encoder memory 183 constituted by a nonvolatile storagedevice capable of electrically reading and writing, an encoder CPU 185for controlling the encoder 9, and a capacitor 187 for attenuating thevalue of a supply voltage at the encoder controlling unit 180 by apredetermined time constant.

Referring to FIGS. 1 and 2, a description will be given of thecontroller for a sewing machine which is configured as described above.The read switch 136 of the operating section 30 is turned on from an offstate (Step 201), whereupon a display unit 36 displays "UPSRE" (Step203), and a control CPU 53 prompts the transfer of the upper-positionangle of the sewing machine stored in a control memory 55 from thecontrol section 40 to the operating section 30. Here, if the read switch136 is turned on (Step 205), the control CPU 53 reads the upper-positionangle of a needle 5 from the control memory 55, transfers theupper-position angle to the operating section 30 through an I/O 51 (Step207), and stores the upper-position angle in the command memory 131(Step 209).

Here, if the control section 40 is replaced with another control section40 due to some cause or other, since the upper-position angle is notstored in the control memory 55, the upper-position angle is stored inthe control memory 55, as will be described below.

First, if the write switch 138 of the operating section 30 is turned on(Step 251), the display unit 36 displays "UPSWR," thereby displaying astate in which the upper-position angle of the needle 5 stored in thecommand memory 131 can be transferred to the control memory 55 (Step253). Here, if the write switch 138 is turned on (Step 255), the controlCPU 53 reads the upper-position angle of the needle 5 from the commandmemory 131, transfers the upper-position angle to the control section 40through the I/O 51 (Step 257), and stores the upper-position angle inthe control memory 55 (Step 259).

It should be noted that although, in the above-described embodiment, theupper-position angle of the needle 5 is stored in the command memory131, and the data in the command memory 131 is stored in the controlmemory 55, the upper-position angle may be stored in the encoder memory183 and the data in the encoder memory 183 may be stored in the controlmemory 55.

Second Embodiment

Referring to FIG. 3, a description will be given of another embodimentof the present invention. In this embodiment, the replacement of themotor is detected by the attenuation of a voltage value of the powersupply of the control section 40, and, for example, a predeterminedangle is set for the needle 5. At the time of shipment, for instance, anidentification number of a motor 7 is inputted to an unillustrated inputdevice, and the identification number of the motor 7 is written in theencoder memory 183 of the motor 7 through this identification number.

The CPU 53 of the control section reads the identification number fromthe encoder memory 183 as the power supply is turned on from the offstate, transfers this number to the control section 40, and stores it inthe control memory 55 (Step 301).

Next, a determination is made whether the power supply of the controlsection 40 can be turned off from an on state due to the failure of themotor 7 attributable to some cause or other (Step 303). If the powersupply can be turned off from the on state, the motor 7 (including theencoder 9) is replaced, and a determination is made as to whether or notthe power supply can be turned on from the off state (Step 305). If thepower supply can be turned on from the off state, the control CPU 53reads from the control memory 55 a first identification number of themotor at the time when the power supply was turned off on the occasionbefore the last, and the control CPU 53 reads a second identificationnumber from the encoder memory 183 and compares the first and secondidentification numbers (Step 307). If they agree with each other, thisprocessing ends.

On the other hand, if the identification numbers do not agree with eachother, the control CPU 53 prohibits the starting of the motor 7 (Step309), and displays an error message on the display unit 36 of theoperating section 30 (Step 311). Then, the control CPU 53 determineswhether or not an angle setting switch 34 has been turned on (Step 313),and if it has been turned on, the operation automatically proceeds tothe aforementioned upper-position-angle setting mode (Step 315). Namely,as showun in FIG. 7, after the operator moved the needle 5 to theposition of the upper position, i.e., to A in the sawtooth outputwaveform of the encoder 9, if the operator turns on the angle settingswitch 34, the display unit displays "UPSET," and the state is set inthe set standby state. If the angle setting switch 34 is turned on, thevalue A of the upper-position angle is stored in the control memory 55,and at this upper-position angle, the sewing machine is readilyoperable.

Third Embodiment

Referring to FIG. 4, a description will be given of still anotherembodiment of the present invention. In this embodiment, the replacementof the motor is detected by, for example, the attenuation of the voltageat the encoder controlling section 180 so as to set the needle at apredetermined angle.

The voltage detecting unit 181 determines whether or not the value ofthe supply voltage at the encoder controlling section 180 has attenuated(Step 401), and if the supply voltage value is normal, this processingends. On the other hand, if the supply voltage value has attenuated, theencoder CPU 185 stores in the encoder memory 183 the fact that the valueof the supply voltage at the encoder controlling section 180 is abnormal(Step 403). The voltage detecting unit 181 then determines whether ornot the value of the supply voltage, after attenuating and becoming off,has returned to normal (on) (Step 405), and if the voltage value has notreturned, this processing ends.

On the other hand, if the supply voltage value has returned, the encoderCPU 185 transfers to the control section 40 the fact that the supplyvoltage value has become abnormal (Step 407). The control CPU 53 thenprohibits the starting of the motor 7 (Step 409), and displays an errormessage on the display unit 36 of the operating section 30 (Step 411).Then, the control CPU 53 determines whether or not the angle settingswitch 34 has been turned on (Step 413), and if it has been turned on,the operation automatically proceeds to the aforementionedupper-position-angle setting mode (Step 415).

It should be noted that, in the above-described second and thirdembodiments, an arrangement may be provided such that the starting ofthe motor is prohibited, and the step of displaying an error is omitted,and the operation proceeds directly to the upper-position-angle settingmode.

As described above, according to a first aspect of the presentinvention, in the controller for a sewing machine in accordance with thefirst aspect of the invention, an advantage can be obtained in thatsince a predetermined positional angle of the needle is stored in thedetecting unit or the designating unit, even if the control section hasbroken down and is replaced with another control section, the resettingof the predetermined positional angle of the needle becomes unnecessary.

According to a second aspect of the present invention, in the controllerfor a sewing machine, an advantage can be obtained in that since thestarting of the motor is prohibited after detecting the replacement ofthe motor, the sewn object can be easily removed, and the needle isprevented from becoming broken.

According to a third aspect of the present invention, in the controllerfor a sewing machine, an advantage can be obtained in that since thepredetermined position of the needle is detected after detecting thereplacement of the motor, the sewn object can be easily removed, and theneedle is prevented from becoming broken.

According to a fourth aspect of the present invention, in the controllerfor a sewing machine, in addition to the advantage of the second orthird aspect of the invention, an advantage can be obtained in thatsince the motor-replacement detecting means makes the determination bythe identification number of the motor, the replacement of the motor canbe detected easily and reliably.

According to a fifth aspect of the present invention, in the controllerfor a sewing machine, in addition to the advantage of the second orthird aspect of the invention, an advantage can be obtained in thatsince the motor-replacement detecting means makes the determination onthe basis of the attenuation of the voltage at the detecting unit, thereplacement of the motor can be detected easily and reliably.

INDUSTRIAL APPLICABILITY

As described above, the controller for a sewing machine in accordancewith the present invention is suitable for designating the position ofthe needle.

What is claimed is:
 1. A controller for a sewing machine, comprising:adriving motor for driving a main shaft of a sewing machine head; adetecting unit having a rotation-angle detecting means or detecting arotational angle of said motor; a control unit for controlling saidmotor and receiving detection signal of said detecting unit; anoperating section for instructing the operation of said sewing machine;a designating means provided in said control unit or said operatingsection for designating a predetermined position in a vertically movingprocess of a needle of said sewing machine; and a first memory portionand a second memory portion for storing and reading a value designatedby said designating means, wherein said first memory portion is providedin said control section, and said second memory portion is provided insaid detecting unit or said operating section.
 2. A controller for asewing machine, comprising:a driving motor for driving a main shaft of asewing machine head; a motor-replacement detecting means for detectingthat said motor has been replaced with another motor; and a startingprohibiting means for prohibiting the starting of said motor if thereplacement is detected by said motor-replacement detecting means.
 3. Acontroller for a sewing machine, comprising:a driving motor for drivinga main shaft of a sewing machine head; a motor-replacement detectingmeans for detecting that said motor has been replaced with anothermotor; and a designating means for designating a predetermined positionof the needle if the replacement is detected by said motor-replacementdetecting means.
 4. The controller for a sewing machine according toclaim 2 or 3, wherein said motor-replacement detecting means comprises:avalue designating means for designating an identification value of saidmotor; an identification-value storing means for storing theidentification value designated by said value designating means; and adetermining means for determining whether or not the identificationvalue of said motor and the identification value of another motor agreewith each other.
 5. The controller for a sewing machine according toclaim 2 or 3, wherein said motor-replacement detecting means comprises:avoltage detecting unit for effecting the detection by the attenuation ofa voltage value of said detecting unit, an assumption being made on thebasis of the attenuation of the voltage value of said voltage detectingunit that said motor has been replaced.